* {
    padding   : 0;
    margin    : 0;
    box-sizing: border-box;
}

@media screen and (max-width:750px) {
    html {
        font-size: 13.3333vw;
    }
}

body {
    background-color: rgba(43, 46, 46, 0.9);
    filter          : drop-shadow(0 0 10px white);
}

.content {
    /*     position: relative; */
}

.content-introduce {
    position  : absolute;
    width     : 600px;
    z-index   : 999;
    left      : 50%;
    margin-top: 160px;
    transform : translateX(-50%);
    color     : #fff;
    text-align: center;
}

.content-introduce img {
    width         : 30px;
    height        : 30px;
    border-radius : 30%;
    vertical-align: middle;
}

.snow {
    position     : absolute;
    width        : 10px;
    height       : 10px;
    left         : 20px;
    background   : rgba(255, 255, 255, 1);
    border-radius: 50%;
}

.content-background {
    position: absolute;
    width   : 100%;
    height  : 569px;
    left    : 0;
    top     : 0;
}

.background-first {
    position  : absolute;
    margin-top: 320px;
    width     : 100%;
    height    : 336px;
    background: url(../img/bg1.png) no-repeat;
    animation : first-bg 70s linear infinite;
    z-index   : 1;
}

.background-second {
    position  : absolute;
    width     : 100%;
    height    : 569px;
    background: url(../img/bg2.png) no-repeat;
    animation : second-bg 85s linear infinite;
}

footer {
    position  : absolute;
    margin-top: 520px;
    width     : 200px;
    height    : 100px;
    background: url(../img/bear.png) no-repeat;
    animation : bearMove 1s steps(8) infinite, Move 5s linear forwards;
    z-index   : 1;
}

@keyframes bearMove {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: -1600px 0;
    }
}

@keyframes Move {
    0% {
        left: 0%;
    }

    100% {
        left     : 50%;
        transform: translateX(-50%);
    }
}

@keyframes first-bg {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: -2400px 0;
    }
}

@keyframes second-bg {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: -2400px 0;
    }
}